In recent years, as mobile devices have been increasingly developed and the demand for such mobile devices has increased, the demand for secondary batteries, which can be charged and discharged, as an energy source for such mobile devices has also sharply increased. As a result, much research has been carried out into a secondary battery that is capable of satisfying the wide variety of demands. In addition, the secondary battery has also attracted considerable attention as a power source for electric vehicles (EV), hybrid electric vehicles (HEV), and plug-in hybrid electric vehicles (PLUG-IN HEV), which have been developed to solve problems, such as air pollution, caused by existing gasoline and diesel vehicles, which use fossil fuels.
Consequently, electric vehicles (EV), which can be driven using only a secondary battery, and hybrid electric vehicles (HEV), which uses both a secondary battery and an engine, have been developed, and some of the electric vehicles (EV) and the hybrid electric vehicles (HEV) have now been commercialized. Nickel-metal hydride (Ni-MH) secondary batteries have been mainly used as a power source for the electric vehicles (EV) and the hybrid electric vehicles (HEV). In recent years, on the other hand, much research has also been carried out into lithium secondary batteries having high energy density, discharge voltage, and output stability, and some of the lithium secondary batteries have now been commercialized.
In the case in which such a secondary battery is used as a power source of a vehicle, the secondary battery is used as a battery pack including a plurality of battery modules or a battery module assembly.
The size and weight of a battery module is directly related to the accommodation space and output of a corresponding middle or large-sized device. For this reason, manufacturers are trying to manufacture battery modules that have as small a size and weight as possible while maintaining the same capacity. In addition, devices, such as an electric bicycle and an electric vehicle, which are subject to a large number of external impacts and vibrations, require stable electrical connection and physical coupling between components constituting the battery module. Furthermore, a plurality of battery cells is used to accomplish high output and large capacity; therefore, the safety of the battery module is regarded as important.
Preferably, a middle or large-sized battery module is manufactured so as to have as small a size and weight as possible. For this reason, a prismatic battery or a pouch-shaped battery cell, which can be stacked with high integration and has a small weight to capacity ratio, is usually used as a battery cell of a middle or large-sized battery module. In particular, much interest is currently focused on the pouch-shaped battery cell, which uses an aluminum laminate sheet as a sheathing member, because the pouch-shaped battery cell is lightweight and the manufacturing cost of the pouch-shaped battery cell is low.
Specifically, the mechanical strength of the pouch-shaped battery cell is low, with the result that additional members are required in order to stably maintain the coupled and assembled state of battery cells when the battery cells are stacked to manufacture a battery module. When the pouch-shaped battery cells are used to manufacture a battery module, an additional mounting member, such as a cartridge, to which one or more battery cells are mounted, is used. A plurality of mounting members is stacked to manufacture a battery module.
However, in the case in which the battery cells are not mounted in position to the cartridge or in the case in which the state in which the battery cells are mounted to the cartridge is not maintained due to the application of external force to a device, various problems, such as disconnection or a short circuit, may occur.